issues with colorado brewing systems fermntation / cellar controller

[BSBC]

We have a Colorado Brewing Systems , Fermentation / cellar controller. It is their top of the line system with touch screen and internet capability. We have noticed that the k type thermocouplers that they require to be used with their system are not at all accurate. They are 8 to 10 degrees off when checked with a handheld digital temp tester and i have confirmed that with an analog tester as well. We have run type k cable, made sure the cable was not interfered with lite fixtures and has no bleed through ambient voltage to throw off the readings. No matter what we do they are off. There is no way of adjusting the controller to compensate for this and CBS cannot give me an answer on this anomaly.

Through my research i have found numerous examples that state that Type K thermocouplers are not accurate at low temps and that type pt100 couplers are much more accurate yet CBS says that i cannot use them with this system. We have an ABS system that uses them and have not had any issues with them yet pt100 couplers are 3 wire where type k are only 2. One wire is a ground.

Has anyone else had this issue with this system? If so how did you fix it?

Thanks in advance.

[TGTimm]

You might want to look up the manual for the actual temp controllers used. Many can use either input by wiring the input right.

[UnFermentable]

What he said....

Most controllers you find nowadays will accept a pt100 input. You should be able to tell when cycling through your controllers options if you don’t have the manual handy. Verify you are on K type currently before concluding the problem.

RTDs for brewing applications, this is fairly easy to understand, but the “book” engineers always think they know better. 3 wire is your friend, skip the 4 wire. Use shielded wire always, IMHO.

K type are a nickel/chromium, nickel/aluminum bi-metal type primarily used in high temp applications which are corrosive or oxidative. They are inaccurate towards the extremes (0*C and 1290*C ?)

FWIW, I used to operate a pilot plant with 350 K-types in a 700*C reactor. They are extremely accurate when used correctly with a proper controller/PID

[gitchegumee]

Although I'd use 3-wire PT100 RTDs on new installations, I've used type K thermocouples on hundreds of tanks with no issues. They are far more accurate than you need when matched to a display/controller properly. You've got something else going on. One thing I've seen done wrong is splicing the thermocouple. Don't do that. They need to run their full length without a splice. There are special splicings available, but don't use them if you don't have to. You also need to review the settings for the controller to be sure you've selected the correct input, offset, hysteresis, and other parameters that must be set right. To reiterate: there is nothing wrong with type K thermocouples in a brewery environment. They are (or can be made) accurate for all temperatures monitored in a brewery.

[TGTimm]

A couple more points:

Make sure the thermowells where your probes are inserted are sealed against ambient air entry. Most purpose-built probes incorporate a seal of some kind, but a good dose of thermal grease at the inner end of the thermowell will also do the trick.

Be sure your probes are seated at the inner end of the thermowell. Again, most purpose-built probes have a spring to ensure good contact.

If the "handheld digital temp tester" is a non-contact IR ("laser") type, don't trust it. The readings depend on the emissivity spectrum of the material being measured. For that matter, don't trust any thermometer that has not been tested and calibrated! Especially dial-type thermos--these are frequently far off if not calibrated regularly. You can use a mixture of ice and water to get a 0C calibration point, which is good for temps in that range. For higher ranges, you need to get a good, certified Mercury In Glass thermometer made for the range you'll be measuring.

[augiedoggy]

There are many proprietary systems based on arduino or other plc/ microcontroller hardware that does not include the additional hardware for RTD probes... CBS would know what their system supports. an example would be "BCS" controllers.

I have multiple types in my panels and they all require different hardware I had to install to allow them to function. That same is not true with standard pids which often accept multiple types by default.

[Ogie]

Wondering if OP ever resolved this inaccuracy issue?